Stereoscopic optical system of a surgical instrument and method for producing same

ABSTRACT

A stereoscopic optical system including: left and right channels; an electromagnetic actuator including a stator and rotor; wherein first optical components of the left channel are arranged in a left tube and second optical components of the right channel are arranged in a right tube; the stator is arranged outside the guide tubes; the rotor includes a left rotor, in which one or more of the first optical components is accommodated, and a right rotor, in which one or more of the second optical components is accommodated; the left and right rotors are mounted in one of the left and right tubes to be movable in a longitudinal axial direction; the left and right rotors include paramagnetic and/or ferromagnetic material and are movable by an electromagnetic field; the stator includes distal and proximal permanent magnets oppositely polarized; and the stator includes an electric coil for generating the electromagnet field.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of PCT/EP2018/057351 filed onMar. 22, 2018, which is based upon and claims the benefit to DE 10 2017107 414.7 filed on Apr. 6, 2017, the entire contents of each of whichare incorporated herein by reference.

BACKGROUND Field

The present disclosure relates to a stereoscopic optical system of asurgical instrument, comprising a left optical channel, a right opticalchannel and an electromagnetic actuator with a stator and a rotor. Thepresent disclosure further relates to a surgical instrument as well as amethod for producing a stereoscopic optical system of a surgicalinstrument, having a left optical channel, a right optical channel andan electromagnetic actuator with a stator and a rotor.

Prior Art

Electromagnetic actuators have many and varied applications. Forexample, switches can be operated, or micro-optics set or adjusted, withthem. In the case of surgical instruments, for example endoscopes, thesecompact-design actuators can be used in order to alter a focus or amagnification of an optical system. In the case of endoscopes having avariable viewing direction, it is in addition possible to set or alter aviewing direction of the optical system with the aid of anelectromagnetic actuator. The optical characteristics of an opticalsystem are altered by moving an optical component, for example a lens, aprism or an aperture by means of the actuator, wherein the opticalcomponent is located in or on the rotor of the actuator.

Bistable and monostable electromagnetic actuators are known. In the caseof a bistable electromagnetic actuator, a rotor is provided, which isheld in a permanent magnetic field in one of two extreme positions (endpositions) and, by switching an electromagnetic field, can betransferred from one of these two stable positions into the other stableposition respectively. In the case of a monostable electromagneticactuator, the rotor is held stably in its resting position by a magneticfield which is generated by one or more permanent magnets. As a resultof applying an electromagnetic field generated by a magnetic coil, therotor is moved out of said stable resting position. Bistable systems aresuitable for two-stage operation with end positions which are maintainedwithout power. On the other hand, monostable systems are suitable forcontinual adjustment.

As already indicated, electromagnetic actuators can be deployed in orderto set or adjust an optical system of a surgical instrument. The opticalsystem of a stereo endoscope comprises two lenses which are ideally setor focused simultaneously with one another. To this end, it would bepossible to deploy two separate electromagnetic actuators as wouldotherwise be deployed to adjust individual optics. However, this isassociated with high costs. In addition, it is desirable if the opticalaxes of the two lenses, which are deployed for the stereoscopic imaging,observe the largest possible distance, the so-called stereo distance,from one another. A large stereo distance makes a good 3D effectpossible. At the same time, luminous optics are desirable such that, ifpossible, lenses having as large a diameter as possible are to be used.The larger the optical elements become, the smaller the availabledistance between the lenses. If the stereo distance is to be keptconstant, the diameter of a tube surrounding the two lenses increases.In addition, the electromagnetic actuators have to be accommodated. Therequirements indicated are therefore more or less in directcontradiction to the restricted installation space present in the tubeof the endoscope.

SUMMARY

It is an object to provide a stereoscopic optical system, a surgicalinstrument having a stereoscopic optical system as well as a method forproducing a stereoscopic optical system, which is improved with respectto the prior art, for example, has a compact design.

Such object can be achieved by a stereoscopic optical system of asurgical instrument, comprising a left optical channel, a right opticalchannel and an electromagnetic actuator with a stator and a rotor,wherein the optical components of the left optical channel are arrangedin a left guide tube and optical components of the right optical channelare arranged in a separate right guide tube, wherein the stator isarranged outside the guide tubes and the rotor comprises a left rotor,in which at least one optical component of the left optical channel isaccommodated, and a right rotor, in which at least one optical componentof the right optical channel is accommodated, and wherein the left andthe right rotor are mounted in the respective guide tube such that theycan move in a longitudinal axial direction of the left and right guidetube, wherein the rotors each at least partially comprise a paramagneticand/or ferromagnetic material and can be moved in the longitudinal axialdirection by application of an electromagnetic field, wherein the statorcomprises a distal permanent magnet and a proximal permanent magnetwhich are oppositely polarized in the longitudinal axial direction, andwherein the stator comprises an electric coil for generating theelectromagnetic field.

The left and the right guide tube can be aligned parallel to oneanother, which means that a longitudinal axial direction of the leftguide tube can be oriented parallel to a longitudinal axial direction ofthe right guide tube. If it is not necessary to distinguish between theleft and the right guide tube, reference is also made below in generalto a longitudinal axial direction which can be oriented in the samedirection as the longitudinal axial directions of the left and rightguide tube. It is also provided that the left and the right guide tubecan enclose an angle of, for example, 2°. This angle between thelongitudinal axial direction of the left guide tube and the longitudinalaxial direction of the right guide tube can be less than 5°. Ifreference is purely made to a longitudinal axial direction and the leftand the right guide tube enclose an angle, said longitudinal axialdirection can be located in the center between the longitudinal axialdirection of the left guide tube and the longitudinal axial direction ofthe right guide tube.

In the stereoscopic optical system the right rotor and the left rotorcan be operated with the aid of a single and joint electromagneticactuator. It can be technically simple and, in addition, can beinexpensive to realize such a construction. In addition, saidconstruction can only take up a very small installation space.

Since separate guide tubes for the left optical channel and the rightoptical channel can be provided, a joint holder can be provided for bothoptical channels or respectively for the optical components thereof.Such a holder can be secured or respectively fixed with respect torotation about its longitudinal axial direction to avoid a subsequenttwisting of the optics with respect to the remaining optical componentsof the stereoscopic optical system, for example of the image sensors.Such rotation can be possible, for example, by deploying a key, inwhich, for example, a clearance fit can be used in order to makepossible the desired axial movability. In another variation, a holderhaving an oval cross-section can be used where the holder slides in asuitable oval bore of a sliding tube. However, such a construction wouldrequire an oval cross-section which may be more expensive to manufactureand may be less precise.

A separate guide tube can also be provided for each of the left rotorand the right rotor. The guide tubes can have a circular cross-section.

According to an embodiment, a distal end of the stator can be formed bya distal stator pole shoe and an opposite proximal end in thelongitudinal axial direction can be formed by a proximal stator poleshoe. Furthermore, the stator can comprise a central stator pole shoewhich is arranged between the permanent magnets in the longitudinalaxial direction. The central stator pole shoe can be formed from aproximal central stator part pole shoe and from a distal central statorpart pole shoe. An air gap can be provided between the distal centralstator part pole shoe and the proximal central stator part pole shoe.

The coil can comprise a distal coil and a proximal coil, wherein thedistal stator pole shoe, a distal coil, the distal permanent magnet andthe distal central stator part pole shoe can form a prefabricated distalassembly and the proximal central stator part pole shoe, a proximalcoil, the proximal permanent magnet and the proximal stator pole shoecan form a prefabricated proximal assembly, wherein the components ofthe distal and/or the proximal assembly can be bonded to one another.

Using stator pole shoes can increase the efficiency of theelectromagnetic actuator thanks to an improved magnetic flow guidance.As a result, larger retention forces can be provided or lower controlcurrents can be deployed.

The central stator pole shoe can be thicker than the outer stator poleshoes, i.e. the distal stator pole shoe or the proximal stator poleshoe. For example, the central stator pole shoe can have a materialthickness, measured in the longitudinal axial direction, which is1.2-times to double the size of the material thickness of the outer poleshoes measured in the same direction.

The air gap between the distal central stator part pole shoe and theproximal central stator part pole shoe can form a distal and a proximalassembly which are not mechanically connected to one another. Since thepermanent magnets of the two assemblies repel one another due to theiroppositely polarized orientation, the two assemblies can be alignedautonomously and independently of any existing component tolerances witha distal and a proximal stop. The use of an adhesive for connecting thetwo assemblies can be dispensed with. If a mechanical connection of thetwo assemblies is to be produced, an adhesive can be deployed, which canhave a low volume shrinkage during curing. For example, an adhesivewhich loses less than 5% volume during curing can be used.

The distal assembly and the proximal assembly can have an identicalconstruction to one another. In order to realize the opposite magneticorientation of the permanent magnets in the electromagnetic actuator,either the proximal assembly or the distal assembly can be installed,rotated by 180° with respect to the other assembly in each case duringerection. The assemblies can be wired appropriately such that theygenerate magnetic fields having the same orientation. Usingprefabricated assemblies can accelerate the production of theelectromagnetic actuator.

According to a further embodiment, the left and the right guide tube canbe accommodated in a joint component which has a dumbbell-shapedcross-section in a plane transversely to the longitudinal axialdirection, and wherein an inner contour of the pole shoes can correspondto an outer contour of the dumbbell-shaped component and an outercontour of the pole shoes can be in the form of a circular segment, atleast in sections.

The two optical channels, i.e. the two guide tubes, can be accommodatedin a joint component or can be provided by such a component. In order toachieve a high efficiency of the actuator, the stator pole shoes can belocated as close as possible to the rotor. For example, the stator poleshoes can have a geometry, into which two bores are introduced in orderto receive the respective receiving tubes. However, such a constructioncan result in a very narrow crosspiece between the two bores, with thecorresponding mechanical instabilities. The central component, in whichthe two receiving tubes are accommodated, can be in the shape of adumbbell. The stator pole shoes can reach up to the outer surface ofsaid dumbbell-shaped component. Thus, a huge mechanical stability can beachieved, on the one hand, which can simplify the assembly of thesystem. At the same time, the stator pole shoes can be positionedsufficiently close to the rotors such that an efficient magnetic flowguidance can be provided.

It is additionally provided that the stator pole shoes can extend in aradial direction perpendicular to the longitudinal axial direction froman outer side of the dumbbell-shaped component up to an outer side ofthe permanent magnets facing away from the dumbbell-shaped componentand/or up to an outer side of the magnetic coils facing away from thedumbbell-shaped component. The flow guidance can be improved by such aconfiguration.

According to a further embodiment, the coil can comprise a distal coiland a proximal coil, wherein the two coils can extend in thelongitudinal axial direction on both sides of the central stator poleshoe and can be electrically coupled to one another such that the distalcoil generates a first magnetic field which is oriented similarly to asecond magnetic field generated by the proximal coil. Thanks to thedivision of the magnetic coil into a first coil and a second coil, saidmagnetic coil can be integrated into the prefabricated proximal assemblyand the prefabricated distal assembly.

In a further embodiment, the coil can surround the left and the rightguide tube and can be oval in a plane arranged perpendicular to thelongitudinal axial direction. The coil can have the form of twosemi-circular segments, with straight pieces being inserted in each casebetween the ends of said semi-circular segments located on one side. Inother words, the form of the coil can correspond, for example, to theform of a track. Creating such a geometry of the coil can require anacceptable outlay, but allows the magnetic flow to be coupledefficiently into the crucial regions of the electromagnetic actuator.The form of the coil can be adapted to an outer contour of the guidetubes. Individual coils can be used for each optical channel. However,an oval coil, which acts jointly for both guide tubes, can be lessexpensive and, in addition, can be a space-saving solution.

According to a further embodiment, the permanent magnets can be arrangedon an outer side of the coil facing away from the guide tubes. Such adesign can be compact since an external magnetic return element can bedispensed with. The permanent magnets can act as magnetic returnelements, at least in regions.

It is additionally provided that the permanent magnets can beblock-shaped magnets which can be arranged in two groups, wherein thegroups can be arranged opposite one another on a flat side each of anarrangement formed from the left and right guide tube. Installationspace can be provided on the flat sides of the guide tubes located nextto one another since the endoscope tube, in which the unit isaccommodated, can have a circular inside diameter. The optics of theright and left channel can be positioned as far as possible from oneanother in order to thus realize a large stereo base. The block-shapedpermanent magnets can be accommodated in the remaining installationspace.

On the flat sides of the tubes located next to one another, availableinstallation space can be provided with a circular receiving opening.Said flat sides can be located at least approximately parallel to adistance of the two tubes. However, no available installation spaceexists on the front sides which can be located perpendicularly to saidflat sides, that is to say in a plane at least approximatelyperpendicular to the distance between the two tubes, since the two tubescan be placed next to one another in the circular receiving opening withas large a distance as possible. Since the coils may be wound with auniform wall thickness, it may not be possible to save on the materialof the coils on said front sides of the arrangement. The material of thestator and the material of the permanent magnets can, however, bedispensed with on the front sides. The flat sides can be utilized inorder to house the permanent magnets. Magnetic disks can be used whichcan have a very thin wall thickness, at least in sections. Sincemagnetic material can be brittle, the handling of such magnetic diskscan be very difficult during the erection of the stereoscopic opticalsystem. Magnetic blocks can be, on the other hand, stable and, inaddition, simple and inexpensive to produce. Additionally, thearrangement of the magnets in the indicated region can bring about acompensation of the magnetic flow guidance influenced by the form of thestator pole shoes.

According to a further embodiment, the permanent magnets can formmagnetic return elements for the magnetic field generated by theelectric coil. Thus, separate magnetic return elements can be avoided,which can decrease the design of the electromagnetic actuator.

According to a further embodiment, at least one of the permanent magnetscan comprise magnetically hard particles which can be embedded in aplastic matrix, wherein said permanent magnet can be produced using aninjection molding method and at least one coil wire of the coil can bemolded in at least one permanent magnet. For example, NdFeB particles(neodymium iron boron) or a mixture of said materials, which can bestirred into an epoxy resin adhesive, is/are suitable as magneticparticles. In order to produce the permanent magnets, a cavity betweenthe stator pole shoes can be emptied. Said cavity can be subsequentlyoccupied by the permanent magnet thus produced. During said operationnot only can the permanent magnet itself be produced, but the parts ofthe assemblies can also be connected or respectively molded together. Itis for example provided that the assembly thus produced can besubsequently magnetized such that the magnetic particles assume thedesired magnetic orientation.

Such object can in addition be achieved by a surgical instrument, suchas an endoscope, having a stereoscopic optical system according to oneor more of the embodiments indicated above.

The surgical instrument can be produced economically and efficiently. Inaddition, a large stereo base can be realized in such a system, such asfor use with the imaging characteristics of a surgical instrument, suchas an endoscope. Moreover, the same or similar advantages apply to thesurgical instrument as have already been mentioned with respect to thestereoscopic optical system itself such that repetitions shall bedispensed with.

Such object can be, in addition, achieved by a method for producing astereoscopic optical system of a surgical instrument, having a leftoptical channel, a right optical channel and an electromagnetic actuatorwith a stator and a rotor, characterized in that optical components ofthe left optical channel are arranged in a left guide tube and opticalcomponents of the right optical channel are arranged in a separate rightguide tube, wherein the stator is arranged outside the guide tubes andthe rotor comprises a left rotor, in which at least one opticalcomponent of the left optical channel is accommodated, and a rightrotor, in which at least one optical component of the right opticalchannel is accommodated, and wherein the left and the right rotor aremounted in the respective guide tube such that they can move in alongitudinal axial direction of the left and right guide tube, whereinthe rotors each at least partially comprise a paramagnetic and/orferromagnetic material and can be moved in the longitudinal axialdirection by application of an electromagnetic field, wherein a distalpermanent magnet and a proximal permanent magnet are arranged in thestator in such a way that they are oppositely polarized in thelongitudinal axial direction, and wherein an electric coil forgenerating the electromagnet field is arranged in the stator.

The same or similar advantages also apply to the method for producing astereoscopic optical system as have already been mentioned with respectto the stereoscopic optical system itself.

According to an embodiment, a distal end of the stator can be formed bya distal stator pole shoe and an opposite proximal end in thelongitudinal axial direction can be formed by a proximal stator poleshoe, and the stator can comprise a central stator pole shoe which canbe arranged between the permanent magnets in the longitudinal axialdirection and can be formed from a proximal central stator part poleshoe and from a distal central stator part pole shoe, wherein a distalassembly is prefabricated in that the distal stator pole shoe, a distalcoil, the distal permanent magnet and the distal central stator partpole shoe can be bonded to one another and a proximal assembly can beprefabricated in that the proximal central stator part pole shoe, aproximal coil, the proximal permanent magnet and the proximal statorpole shoe can be bonded to one another.

The permanent magnets can be block-shaped magnets, wherein the magnetscan be arranged in two groups and the groups can be arranged oppositeone another on a flat side each of an arrangement formed from the leftand right guide tube.

At least one of the permanent magnets can be produced in thatmagnetically hard particles can be embedded in a plastic matrix, whereinsaid permanent magnet can be produced using an injection molding methodand at least one coil wire of the coil can be molded in at least onepermanent magnet.

Further features will become evident from the description ofembodiments, together with the claims and the appended drawings.Embodiments can fulfill individual features or a combination of severalfeatures.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments are described below without limiting the general conceptof the invention by means of exemplary embodiments with reference to thedrawings, wherein reference is expressly made to the drawings regardingall of the details which are not explained in greater detail in thetext, wherein:

FIG. 1 illustrates an endoscope as an exemplary surgical instrument in aschematically simplified perspective view,

FIG. 2 illustrates a stereoscopic optical system in a schematicallysimplified perspective view,

FIG. 3 illustrates said system, wherein a proximal stator pole shoe isremoved, in order to expose the view of the components located behindit,

FIG. 4 show illustrates s a stereoscopic optical system in aschematically simplified sectional view in a plane, in which aconnecting line of the two optical channels is located,

FIG. 5 illustrates a further schematic sectional view in a plane whichis located perpendicular to that plane, in which the sectional viewrepresented in FIG. 4 is located,

FIGS. 6 and 7 each illustrate a schematically simplified sketch in orderto explain the mode of operation of an electromagnetic actuator deployedin a stereoscopic optical system.

In the drawings, the same or similar elements and/or parts are, in eachcase, provided with the same reference numerals such that they are notintroduced again in each case.

DETAILED DESCRIPTION

FIG. 1 shows an endoscope 2 as an exemplary surgical instrument in aschematically simplified perspective view. The endoscope 2 comprises anendoscope shaft (or insertion section) 4, in which an optical system isarranged, with which an operation or observation field lying in front ofa distal end 6 of the endoscope shaft 4 is imaged. A handle 8 is locatedon a proximal end of the endoscope 2. The optical system (notrepresented in FIG. 1) arranged in the endoscope shaft 4 comprises anelectromagnetic actuator.

FIG. 2 shows an exemplary optical system 10, as it can be provided inthe distal end 6 of the endoscope shaft 4 of the endoscope 2. Theoptical system 10 is a stereoscopic system, as shown by the view whichis represented in a schematic, simplified and perspective manner in FIG.2.

FIG. 2 shows an installation situation, in which an endoscope tube whichnormally surrounds the stereoscopic optical system 10 is omitted, inorder to expose the view of the components of the system. Thestereoscopic optical system 10 comprises a left optical channel 12 and aright optical channel 14. The respective front lenses of the opticalchannels 12, 14 of the optical components of the left optical channel 12and of the right optical channel 14 are represented, by way of example,in FIG. 2. The stereoscopic optical system 10 additionally comprises anelectromagnetic actuator 16, comprising a stator 18 and a rotor 20. Theoptical components of the left optical channel 12, for example the frontlens which is visible in FIG. 2, is/are accommodated in a left guidetube 26. This relates to at least a part of the optical components ofthe left optical channel 12. Optical components of the right opticalchannel 14 are arranged in a separate right guide tube 28 to the leftguide tube 26. The two guide tubes 26, 28 are, for example, arrangedparallel to one another. It is, however, likewise provided that theguide tubes 26, 28 are arranged at an angle of, for example, 2° to oneanother, wherein said angle does not as a general rule exceed 5°. Likethe optical components of the left optical channel, the opticalcomponents of the right optical channel 14 are also at least partiallyarranged in the right guide tube 28. The guide tubes 26, 28 are, forexample, separate components, for example tubes. It is likewise providedthat the guide tubes 26, 28 are not separate components and, instead,are provided by bores inset in a dumbbell-shaped component 64.

The stator 18 is arranged outside the guide tubes 26, 28 and enclosesthe guide tubes 26, 28 completely. This applies to a directionperpendicular to a longitudinal axial direction of the guide tubes 26,28. It is not necessary for the stator 18 to completely enclose theguide tubes 26, 28 in a longitudinal axial direction L.

The rotor 20 comprises a left rotor 22, in which at least one opticalcomponent of the left optical channel 12 is accommodated. The rotor 20additionally comprises a right rotor 24, in which at least one opticalcomponent of the right optical channel 14 is accommodated. In therepresented exemplary embodiment, the front lenses of the opticalchannels 12, 14 are each accommodated in the corresponding rotors 22,24.

The left rotor 22 is mounted such that it can move in a leftlongitudinal axial direction LL along the left guide tube 26. The rightrotor 24 is mounted in the right guide tube 28 such that it can movealong a right longitudinal axial direction LR. The left longitudinalaxial direction LL and the right longitudinal axial direction LR (eachindicated with a dot-dashed line) are aligned parallel to one another.They coincide with the central longitudinal axes of the respective guidetubes 26, 28. If it is not necessary to distinguish between the leftlongitudinal axial direction LL and the right longitudinal axialdirection LR below, reference is made in general to a longitudinal axialdirection L which extends parallel to the left and the rightlongitudinal axial direction LL, LR.

The left rotor 22 and the right rotor 24 each at least partiallycomprise a paramagnetic and/or ferromagnetic material. In other words,the rotors 22, 24 are therefore at least partially produced from aparamagnetic and/or a ferromagnetic material. Thus, it is possible tomove the rotors 22, 24 in the associated guide tube 26, 28 in therespective longitudinal axial direction LL, LR by application of anelectromagnetic field 68. The stator 18 comprises a distal permanentmagnet 30 and a proximal permanent magnet 32. The two permanent magnets30, 32 are oppositely polarized in the longitudinal axial direction L.Further details regarding this are explained below in connection withFIGS. 6 and 7.

The stator 18 additionally comprises an electric coil for generating theelectromagnetic field 68. Said coil is only partially visible in FIG. 2.The electromagnetic field 68 generated by it serves to move the rotors22, 24 in their guide tubes 26, 28 along the respective longitudinalaxial direction LL, LR.

FIG. 3 shows the stereoscopic optical system 10 of FIG. 2, likewise in asimplified perspective view, and in an installation situation at adistal end 6 of an endoscope shaft 4. In order to expose the view of thecomponents located behind the electric coil 34 just mentioned, aproximal stator pole shoe is not represented.

The stator 18 of the stereoscopic optical system 10 shown in FIGS. 2 and3 comprises, at its distal end 36, a distal stator pole shoe 38. At itsopposite proximal end 40 in the longitudinal axial direction L, thestator 18 comprises a proximal stator pole shoe 42. In addition, thestator 18 comprises a central stator pole shoe 44 which is arrangedbetween the permanent magnets 30, 32 in the longitudinal axial directionL and is formed, in the exemplary embodiment shown, from a proximalcentral stator part pole shoe 46 and from a distal central stator partpole shoe 48. An air gap 50 is, for example, provided between theproximal central stator part pole shoe 46 and the distal central statorpart pole shoe 48. The coil 34 is divided into a distal coil 52 and aproximal coil 54.

The distal stator pole shoe 38, the distal coil 52, the distal permanentmagnet 30 and the distal central stator part pole shoe 48 form aprefabricated distal assembly 60. The proximal central stator part poleshoe 46, the proximal coil 54, the proximal permanent magnet 32 and theproximal stator pole shoe 42 form a proximal assembly 62. The componentsof the distal assembly 60 are, for example, bonded to one another. Thesame applies to the components of the proximal assembly 62. Thus, it ispossible that prefabricated assemblies 60, 62 are provided and thestereoscopic optical system, more precisely the stator 18 thereof, iscomposed of these. In connection with this, it is for example providedthat the two assemblies 60, 62 are prefabricated in an identical manner.The difference between the distal assembly 60 and the proximal assembly62 is purely the poling, i.e. the alignment, of the permanent magnets30, 32 thereof. In order to provide an opposing orientation of thepermanent magnets 30, 32 of the two assemblies 60, 62, one of the twoassemblies 60, 62 can be installed, rotated by 180° with respect to theother assembly 60, 62.

The permanent magnets 30, 32, which are integrated into the assemblies60, 62, are for example block-shaped magnets. These are additionallyarranged, for example, in multiple groups, wherein the groups can bearranged at positions which are opposite one another. In the representedexemplary embodiment, the permanent magnets 30, 32 are arranged in twogroups. The distal permanent magnet thus comprises the magnetic blockdesignated with reference numeral 30 and reference numeral 30′. Theproximal permanent magnet 32 comprises the block provided above in thelongitudinal axial direction L proximally behind the distal permanentmagnet 30 as well as a further magnetic block 32′, which is not visiblein the figures, which is located proximally behind the distal permanentmagnetic block 30′ in the longitudinal axial direction L. The permanentmagnets 30, 32 are oppositely polarized in the longitudinal axialdirection L. This means that the magnetic blocks repel one another. Saidrepelling force ensures that the distal assembly 60 and the proximalassembly 62 are forced apart such that the air gap 50 remains betweenthem. The distal assembly 60 is pressed against a distal stop, while theproximal assembly 62 is pressed against a proximal stop. The assemblies60, 62 can be aligned without the position attained being dependent oncomponent tolerances.

It is not necessary for the two assemblies 60, 62 to be bonded to oneanother in the installation situation. The repelling magnetic forcesacting between the assemblies are large enough to keep the assemblies60, 62 in place. If the assemblies 60, 62 are to be fixed, an adhesiveis deployed which shows a small volume shrinkage (for example less than5 vol.-%) during the curing process.

The groups of the block-shaped permanent magnets are each arranged on aflat side of an arrangement formed from the right and left guide tube26, 28. FIG. 3 shows such features clearly.

The left guide tube 26 and the right guide tube 28 are accommodated in ajoint component 64. As already indicated, the left guide tube 26 and/orthe right guide tube 28 can be separate components, for example tubes.It is, however, likewise provided that the left guide tube 26 and/or theright guide tube 28 are inset as bores in the joint component 64. Saidjoint component 64 has a dumbbell-shaped cross-section in a planetransversely to the longitudinal axial direction L. An inner contour ofthe pole shoes 38, 48, 46, 42 corresponds to an outer contour of thedumbbell-shaped component 64. An outer contour of the pole shoes 38, 48,46, 42 is in the form of a circular segment, at least in sections. AsFIGS. 2 and 3 show, said sections of the pole shoes 38, 48, 46, 42 arelocated on the front sides of the arrangement formed from the left andright guide tube 26, 28 and not on the flat sides thereof.

The coil 34, i.e. the distal coil 52 and the proximal coil 54,surround(s) the left and right guide tube 26, 28 and is/are oval in aplane arranged perpendicular to the longitudinal axial direction L. Thepermanent magnets 30, 32 are arranged on an outer side 66 of the coil 34facing away from the guide tubes 26, 28. More precisely, the distalpermanent magnet 30, 30′ is arranged on an outer side 66 of the distalcoil 52 and a proximal permanent magnet 32 is arranged on the outer side66 of a proximal coil 54.

Due to their arrangement, the permanent magnets 30, 32 form magneticreturn elements for the electromagnetic field 68 generated by theelectric coil 34.

For example, the permanent magnets 30, 30′, 32, 32′ or only one of thesepermanent magnets is/are produced from a plastic matrix, in whichmagnetic particles such as magnetically hard particles, are embedded.Such a permanent magnet can be produced using an injection moldingmethod. During the production of the permanent magnet 30, 30′, 32, 32′,not only can the permanent magnet itself be produced, but the componentsof the corresponding assembly 60, 62 can also be connected to oneanother. Additionally, a coil wire of the coil 34 can be guided throughthe permanent magnet 30, 30′, 32, 32′, in other words, the coil wire isalso molded.

FIG. 4 shows the stereoscopic optical system 10 in a schematicallysimplified sectional view in a plane, in which a connecting line islocated between the two optical channels 12, 14. The longitudinal axialdirections LL, LR of the left optical channel 12 and of the rightoptical channel 14 are also located in this plane.

FIG. 5 shows a further schematic sectional view in a plane which islocated perpendicular to that plane, in which the sectional viewrepresented in FIG. 4 is located.

The mode of operation of the electromagnetic actuator of thestereoscopic optical system 10 is explained below, with reference to theschematically simplified diagrams in FIGS. 6 and 7.

FIG. 6 shows the electromagnetic actuator 16 in a deenergized condition,in which the rotor thereof, which is purely by way of example the leftrotor 22, is located in a proximal end position. The rotor 22 is movablyaccommodated within the left guide tube 26 in the longitudinal axialdirection L. The stator 18 of the electromagnetic actuator 16 is locatedoutside the guide tube 26. The distal permanent magnet 30 and theproximal permanent magnet 32, which are oppositely polarized, areadditionally represented. The north-south directions of the permanentmagnets 30, 32 are located parallel to the longitudinal axial directionL. A distal stator pole shoe 38 is located at a distal end 36 of thestator 18, a proximal stator pole shoe 42 is located at a proximal end40 of the stator 18. A central stator pole shoe 44 is located betweenthe permanent magnets 30, 32 in the longitudinal axial direction L. Thecoil 34 comprises a distal coil 52 and a proximal coil 54.

FIG. 7 shows the electromagnetic actuator 16, wherein the distal coil 52and the proximal coil 54 are energized. The two coils 52, 54 are coupledto one another such that a first magnetic field generated by therespective coil 52, 54 and a second magnetic field are similarlyoriented. This is the result of the identical energizing of the twocoils 52, 54. The current flow direction is indicated in theschematically sketched conductors of the coils 52, 54. A currentdirection pointing out of the drawing plane is indicated by a dot and acurrent direction directed into the drawing plane is indicated by across. The first and the second magnetic field of the coils 52, 54 addup to produce the electromagnetic field 68 which is represented in adot-dashed manner line.

The electromagnetic field 68 superimposes a first static magnetic field70 which is generated by the distal permanent magnet 30 and a secondstatic magnetic field 72 which is generated by the second permanentmagnet 32. At the distal end 36 of the stator 18, the electromagneticfield 68 and the first static magnetic field 70 are constructivelysuperimposed such that a reinforcement of the total magnetic fieldpresent occurs due to the energizing of the coil 34 on this side of thestator 18. At the proximal end 40 of the stator 18, the electromagneticfield 68 and the second static magnetic field 72, which is generated bythe proximal permanent magnet 32, are in the opposite direction suchthat an attenuation of the total magnetic field present takes place atthis end of the stator 18. Thus, a greater force acts in a gap (which isclosed in the represented situation) between the rotor 22 and the guidetube 26 at the distal end 36 than at the proximal end 40, such that therotor 20 is displaced into the end position shown in FIG. 7. Adisplacement back into the starting position is effected by energizingthe coil 34 accordingly in the opposite direction.

The corresponding components are purely represented in the upper half ofthe drawing in FIGS. 6 and 7. The represented sectional view is,however, rotationally symmetrical to a central longitudinal axis, whichis why the corresponding components can also be similarly found in thelower half of the respective drawing.

While there has been shown and described what is considered to bepreferred embodiments, it will, of course, be understood that variousmodifications and changes in form or detail could readily be madewithout departing from the spirit of the invention. It is thereforeintended that the invention be not limited to the exact forms describedand illustrated, but should be constructed to cover all modificationsthat may fall within the scope of the appended claims.

LIST OF REFERENCE NUMERALS

-   -   2 Endoscope    -   4 Endoscope shaft    -   6 Distal end    -   8 Handle    -   10 Stereoscopic optical system    -   12 Left optical channel    -   14 Right optical channel    -   16 Electromagnetic actuator    -   18 Stator    -   20 Rotor    -   22 Left rotor    -   24 Right rotor    -   26 Left guide tube    -   28 Right guide tube    -   30, 30′ Distal permanent magnet    -   32, 32′ Proximal permanent magnet    -   34 Coil    -   36 Distal end of the stator    -   38 Distal stator pole shoe    -   40 Proximal end of the stator    -   42 Proximal stator pole shoe    -   44 Central stator pole shoe    -   46 Proximal central stator part pole shoe    -   48 Distal central stator part pole shoe    -   50 Air gap    -   52 Distal coil    -   54 Proximal coil    -   60 Distal assembly    -   62 Proximal assembly    -   64 Dumbbell-shaped component    -   66 Outer side    -   68 Electromagnetic field    -   70 First static magnetic field    -   72 Second static magnetic field    -   L Longitudinal axial direction    -   LL Left longitudinal axial direction    -   LR Right longitudinal axial direction

What is claimed is:
 1. A stereoscopic optical system for use with asurgical instrument, the stereoscopic optical system comprising: a leftoptical channel; a right optical channel; and an electromagneticactuator comprising a stator and a rotor; wherein first opticalcomponents of the left optical channel are arranged in a left guide tubeand second optical components of the right optical channel are arrangedin a separate right guide tube; the stator is arranged outside the leftguide tube and the right guide tube; the rotor comprises a left rotor,in which at least one of the first optical components of the leftoptical channel is accommodated, and a right rotor, in which at leastone of the second optical components of the right optical channel isaccommodated; the left rotor and the right rotor are mounted in arespective one of the left guide tube and the right guide tube such thatthe left rotor and the right rotor are movable in a longitudinal axialdirection of the left guide tube and the right guide tube; the leftrotor and the right rotor each at least partially comprise one of aparamagnetic and a ferromagnetic material and are movable in thelongitudinal axial direction by application of an electromagnetic field;the stator comprises a distal permanent magnet and a proximal permanentmagnet which are oppositely polarized in the longitudinal axialdirection; the stator comprises an electric coil for generating theelectromagnet field; and the electric coil surrounds the left guide tubeand the right guide tube.
 2. The stereoscopic optical system accordingto claim 1, wherein: a distal end of the stator is formed by a distalstator pole shoe and an opposite proximal end in the longitudinal axialdirection is formed by a proximal stator pole shoe; the stator furthercomprises a central stator pole shoe arranged between the distalpermanent magnet and the proximal permanent magnet in the longitudinalaxial direction; and the central stator pole shoe is formed from aproximal central stator part pole shoe and from a distal central statorpart pole shoe.
 3. The stereoscopic optical system according to claim 2,wherein: the electric coil comprises a distal coil and a proximal coil;the distal stator pole shoe, the distal coil, the distal permanentmagnet and the distal central stator part pole shoe form a prefabricateddistal assembly; and the proximal central stator part pole shoe, theproximal coil, the proximal permanent magnet and the proximal statorpole shoe form a prefabricated proximal assembly.
 4. The stereoscopicoptical system according to claim 3, wherein one or more of the distalstator pole shoe, the distal coil, the distal permanent magnet and thedistal central stator part pole shoe of the prefabricated distalassembly are bonded together and the proximal central stator part poleshoe, the proximal coil, the proximal permanent magnet and the proximalstator pole shoe of the prefabricated proximal assembly are bondedtogether.
 5. The stereoscopic optical system according to claim 2,wherein: the left guide tube and the right guide tube are accommodatedin a joint component which has a dumbbell-shaped cross-section in aplane transverse to the longitudinal axial direction; and wherein aninner contour of the distal stator pole shoe, the proximal stator poleshoe, the distal central stator part pole shoe and the proximal centralstator part pole shoe correspond to an outer contour of thedumbbell-shaped component and an outer contour of the distal stator poleshoe, the proximal stator pole shoe, the distal central stator part poleshoe and the proximal central stator part pole is in the form of acircular segment at least in sections.
 6. The stereoscopic opticalsystem according to claim 1, wherein the electric coil is oval in aplane oriented perpendicular to the longitudinal axial direction.
 7. Thestereoscopic optical system according to claim 1, wherein the distalpermanent magnet and the proximal permanent magnet are arranged on anouter side of the electric coil facing away from the guide tubes.
 8. Thestereoscopic optical system according to claim 1, wherein the distalpermanent magnet and the proximal permanent magnet are block-shapedmagnets which are arranged in two groups, wherein the two groups arearranged opposite one another on a flat side each of an arrangementformed from the left guide tube and the right guide tube.
 9. Thestereoscopic optical system according to claim 1, wherein the distalpermanent magnet and the proximal permanent magnet form magnetic returnelements for the magnetic field generated by the electric coil.
 10. Thestereoscopic optical system according to claim 1, wherein at least oneof the distal permanent magnet and the proximal permanent magnetcomprises magnetically hard particles which are embedded in a plasticmatrix.
 11. The stereoscopic optical system according to claim 10,wherein at least one coil wire of the electric coil is molded in atleast one of the distal permanent magnet and the proximal permanentmagnet.
 12. A surgical instrument comprising: the left guide tube andthe right guide tube; and the stereoscopic optical system according toclaim
 1. 13. The surgical instrument according to claim 12, wherein theleft guide tube and the right guide tube are provided in an insertionsection of an endoscope.